A sacrificial protective panel is typically a relatively inexpensive transparent sheet of material, such as plastic, protecting a more expensive windowpane or glazing behind it. Generally of the same shape and size as the glazing they protect, sacrificial protective panels are typically positioned against the glazing, with the protective panel desirably absorbing any impact and/or damage directed towards the glazing. Desirably, any damage to the window assembly will be limited to the protective panel, which can be replaced at low cost, thereby significantly increasing the useful life of the window assembly. In addition, various types of solvents which cannot be used on the glass windowpane can often be used on the glazing panels to remove graffiti. Window assemblies employing sacrificial protective panels are commonly used in mass-transit vehicles, particularly buses and trains, where vandalism and wear to the glazing are problems. Use of sacrificial protective panels saves the cost and difficulty incurred with removing and replacing the complete window assembly.
Various types of sacrificial protective panels and mounting arrangements for windows of mass transit vehicles are well known in the art. For example, U.S. Pat. Nos. 5,242,207 and 5,735,089, which are incorporated herein by reference, describe and illustrate window protectors for use in mass transit vehicles. While these arrangements allow the use of sacrificing protective panels, the installation and replacement process of glazing panels in these arrangements is typically a time-intensive process which requires a number of specialized tools to complete. On the other hand, window assemblies incorporating easily-removable sacrificial panels typically also permit vandals to remove these same protective panels, significantly increasing the likelihood of damage to the glazing. In addition, where a protective panel is held in the window assembly by one or more exposed flexible mountings and/or gaskets, such mountings and/or gaskets can easily be damaged by vandals, necessitating expensive and time-consuming replacement of the mountings and/or gaskets as well as the remaining components of the window assembly.
Hence, there is continuing need for improved assemblies for protecting window glazing in mass transit vehicles from damage. While some of the existing assemblies do provide protection, some of the existing assemblies are often more difficult to manipulate such that replacement of the sacrificial protective sheets, or even the glazing itself, is complicated. Generally, it is preferable to be able to quickly replace all of the necessary protective sheets and glazing with a minimum of time and effort in order to keep maintenance costs at a minimum.
Further, existing window protection assemblies typically only protect the inner surface of the glazing. It will be appreciated, however, that both the inner surfaces and the outer surfaces of the glazing can be damaged thereby affecting the appearance of the window.
A need in the art exists, therefore, for a sacrificial protective panel and mounting arrangement in which the glazing panels can be quickly and conveniently replaced with a minimum of specialized tools, but in which the protective panel cannot easily be removed and/or the mounting assembly cannot easily be damaged by non-maintenance personnel. Moreover, this mounting assembly should also be suited for protecting both sides of the glazing of a window and still permit easy replacement and repair.